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View Full Version : [Project] Johnny5 2-DOF Eyelid Prototype.



JadeKnight
02-16-2009, 12:42 AM
I just finished the first prototype for my 2-DOF Johnny5 Eyelid.

I had been thinking of ways to accomplish multi-DOF eyelids for a while. Most of them involved having servos on the eyelids themselves, which wouldn't fit at all. I was doing some work on my RC helicopter, when I noticed the tail mechanics. It rotated and changed the blade pitch, much like the eyelids would need to. That's when inspiration hit me.

So, I grabbed some sub-micro servos (JR DS188's) and a new T-Rex 450 tail assembly, then set about trying to create an eyelid. I eventually got the current design implemented. It is still a little bulky, but I can dremel a lot of the unnecessary pieces off to make it smaller.

In the final design, the 2 servos will be mounted behind the head, with the main rotation shaft going over the top of the head to the front. The shaft is long enough, so that a webcam can sit comfortably between the servos and the eyelid itself. I also plan on adding a lower eyelid using a similar mechanic that has only 1-DOF (I believe the lower eyelids in the movies also only had 1-DOF).

In the end, though, the head on my J-5 may end up being slightly larger than average (basically the width of 4 DS188 servos, or ~2 inches). I think it will be worth it to have the extra articulation.

Here is a video of it running. Sorry about the low framerate / image quality... it's a low quality web-cam.

YouTube - J5 Prototype Eyelid Test

I'll post some close up pictures of the mechanics later.

DresnerRobotics
02-16-2009, 12:48 AM
So, I pretty much love you.

You must post more details on the mechanics behind this and exactly what parts you used (links?), I've been trying to solve this for awhile on my J5...

JadeKnight
02-16-2009, 01:23 AM
Here are some up-close pics of the mechanics.

As you can see in the photos, there is a lot of excess material that can be removed. The other side of the tail hub, most of the blade grip under the eyelid, other half the control slider, etc.

JadeKnight
02-16-2009, 01:33 AM
Here is the parts list for the eyelid prototype.

Linkage Rods
http://www.readyheli.com/HZ010_Servo_Linkage_Rod_Refitting_Components_p/hz010.htm

Tail Rotor Shaft (package of 3, plastic gear would be preferable since you don't need the gear)
http://www.readyheli.com/HS1203_Metal_Tail_Rotor_Shaft_p/hs1203.htm

Tail Rotor Parts (only need control slider, tail hub, and blade grips)
(each can be bought separately, but it's about same price as the whole package)
http://www.readyheli.com/HS1199_Tail_Rotor_Parts_p/hs1199.htm

2x JR DS188 servos (or any suitably small servo)

As for assembly, the tail hub + control slider is pretty simple. The pics should show how they go together. I currently have the tail rotor shaft hot-glued onto the top of one servo's horn. The other servo has a ball link and linkage rod that connects it to the slider.

Currently there is nothing stopping the control slider and linkage rod from rotating slightly. It doesn't affect the functionality much, but it would be more efficient if the control slider was kept inline. Maybe with a guide, or something.